• Journal of the Korean earth science society
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• v.26 no.7
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• pp.674-682
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• 2005

The Samsung mine is located in Jeongsan-myeon, Cheongyang-gun, Chungcheongnam-do, and is produces sericite ores. The purpose of this study is to investigate the geology and mineralogy of sericite one and its host-rock together with the alteration processes and age of sericitization. Geological survey, polarizing microscopy, X-ray powder diffraction, electron microprobe analysis, X-ray fluorescent analysis, differential thermal analysis, and K/Ar isotope study have been employed for this study. The mine area is composed of Precambrian granite-gneiss and mica schist, and also Jurassic biotite granite. Serictization has occured within the granite-gneiss, and is interpreted to be formed by hydrothermal alteration. The sericite was formed by the breakdown of orthoclase, plagioclase, and biotite, respectively. With sericitization intensity increase, $SiO_2\;and\;Na_2O$ contents are decreased, while $Al_2O_3\;and\;K_2O$ increased. The formation age of sericite has been determined to be Jurassic, which corresponds well to the intrusion age of the biotite granite nearby.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2002.11b
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• pp.76-76
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• 2002

무주나무(Lasianthus japonicus Miquel)는 일본, 대만, 중국 등에 분포하고 열대 및 아열대의 상록활엽수림에서만 자라는 것으로 알려져 있으며, 우리나라에는 제주도 남쪽계곡에만 분포하는 희귀식물이다. 무주나무는 현재 환경부 지정 보호야생식물로 보호되고 있으나 개체특성 및 자생지에 대한 정확한 조사가 이루어진 바 없다. 본 연구는 무주나무의 자생지 현황과 생육특성을 파악하고자 실시하였다. 무주나무의 자생지는 제주도 남제주군 남원읍 하례리 해발 250m의 계곡 동사면과 서귀포시 돈네코 계곡의 해발 350 m 계곡의 서사면 등 2개소로 확인되었다. 자생지별 개체수는 남원읍 하례리 4개체, 서귀포시 돈네코계곡 5개체 등 총 9개체에 불과하였다. 자생지는 계곡의 상록수림 하부에 바위 위 부엽토나, 습한 계곡 사면이었으며, 교목층에는 구실잣밤나무, 비쭈기나무, 황칠나무, 동백나무 등이 우점하고, 관목층에는 사스레피나무, 백량금, 산호수 등이 우점하는 상록활엽수림이었다. 분포 개체의 수고는 최소 0.4 m, 최대 1.55 m로 평균 1.5 m 였다. 생장특성을 조사한 결과 줄기는 어릴 때는 사각형이지만 점차 원형으로 되며, 일정한 마디가 있고 털이 없으며, 잎은 대생하고, 혁질이며, 중륵과 측맥이 뚜렷한 특성을 갖고 있었다. 열매는 장과형으로 성숙 시에는 남색이며 털이 없으며, 직경 약 6-7 mm, 4-5개의 종자가 들어 있었다. 종자는 반달형이며, 3개의 홈이 지는 특성을 갖고 있었다. 현재의 자생지는 자연적인 요인으로서 토양유실이 심하게 일어나고 있는 지역이었으며, 교목 또는 다른 관목에 의한 피압으로 무주나무의 생장에 부적절한 환경으로 판단되었다. 따라서 자생지의 적절한 식생관리와 지속적인 자생지 조사 및 자생지외 보존에 관한 연구가 이루어져야할 것으로 생각된다.$I_{NO}$ 가 죽절초를 제외한 3종에서 여름철 낮시간에 증가하였다. 겨울철의 O-J-I-P곡선은 모든 종에서 낮시간에 다소 낮아지지만 큰 변화는 없었다. 그리고, 문주란, 박달목서, 파초일엽에서 $\psi$o/(1-$\psi$o)가 낮시간에 다소 증가하였다. 이로부터 P $I_{NO}$ , SF $I_{NO}$ , $\psi$o/(1-$\psi$o)등의 변수는 식물의 활력도를 검정하는 지표로 활용될 가능성이 높다고 할 수 있다.irc}C$) 까지 동시에 냉각된 사실을 지시한다. 각섬석 편암내의 각섬석들은 복잡한 40Ar/39Ar 연대를 보여주며 일부가 평형연대를 보여주지만 특별한 의미 부여가 힘들다.해예방행동을 촉구하는 등의 효과도 높은 것으로 예방의학적인 유용성이 크다고 볼 수 있다. 미침을 알 수 있었다. 대두 단백질로 코팅된 golden delicious는 상온에서60일 동안 보관하였을 경우, 사과표피의 색도 변화를 현저히 지연시킴을 확인하였다. 또한 control과 비교하여 성공적으로 사과에 코팅하였으며, 상온에서 보관하여을 때 사과의 품질을 30일 이상 연장하는 효과를 관찰하였다. 이들 결과로부터 대두단백질 필름이 과일 등의 포장제로서 이용할 가능성을 확인하였다.로 [-wh] 겹의문사는 복수 의미를 지닐 수 없 다. 그러면 단수 의미는 어떻게 생성되는가\ulcorner 본 논문에서는 표면적 형태에도 불구하고 [-wh]의미의 겹의문사는 병렬적 관계의 합성어가 아니라 내부구조를 지니지 않은 단순한 단어(minimal $X^{0}$ elements)로 가정한다. 즉, [+wh] 의미의 겹의문사는 동일한 구성

• The Journal of the Petrological Society of Korea
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• v.5 no.1
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• pp.52-65
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• 1996

Precambrian metamorphic rocks of the Cheongpyeong-Yangpyeong area, central Gyeonggi massif, comprise gneiss, schist, quartzite and amphibolite. Mineral, assemblages of pelitic gneisses are characterized by biotite + cordierite + garnet + sillimanite + K-feldspar + plagioclase + quartz together with minor muscovite, spinel and corundum, and represent the granulite facies metamorphism. In particular, kyanite occurs as fine-grained relict phase inside plagioclase of three gneiss samples. Metamorphic conditions are estimated from garnet-biotite and garnet-cordierite geothermometers in conjunction with garnet-$Al_2SiO_5$-quartz-plagioclase (GASP) and garnet-rutile-$Al_2SiO_5$-ilmenite (GRAIL) geobarometers. They are 700-$850^{\circ}C$ and 3.2-8.3 kbar, and 580-$690^{\circ}C$ and 2.1-3.2 kbar, respectively, when the core and rim compositions of garnet are use. Garnet of the GASP assemblage increases rimward in the Fe and Mn contents but decreases in the Mg content, whereas its Ca content does not vary significantly. Together with the occurrence of relict kyanite and the result of P-T estimates, compositional zoning patterns of garnet indicate a clockwise P-T history. Moreover, the preservation of high-pressure minerals such as kyanite in plagiocalse, even after the medium-pressure granulite facies metamorphis, suggests a rapid change in P-T conditions.

• Economic and Environmental Geology
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• v.39 no.1 s.176
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• pp.1-7
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• 2006

This paper attempts to locate and define a quartzite deposit in Geochang, Kyongsangnam Province in order to establish its commercial viability. The quartzite deposit (Poongwon Mine) occurs as lens or boudinage at the contact between mica schist of the Deogyusan formation and granite gneiss. During Precambrian, regional metamorphism and granitization may have caused the formation ot quartzite layers through recrystallization and rearrangement of silica components derived from older sedimentary rocks, probably chert and/or sandstone. The deposit is composed of fine-grained milky, or light yellowish quartz showing weak laminations with fairly dense and rough appearance in outcrop. It reaches about $60\;m(height)\times140\;m(length)\times35m(width)$ with attitude of $N57^{\circ}E-N8^{\circ}4E\;and\;51^{\circ}-60^{\circ}NW$. The average grade of the quartzite samples is $SiO_2=94.4\;wt\%,\;A1_2O_3=3.3\;wt\%,\; Fe_2O_3=0.8\;wt\%,\;K_2O=0.7\;wt\%$, which can be used for foundry, constructional materials, or concrete making. The proved reserve was estimated as 200,811 tonnage.

• Journal of the Mineralogical Society of Korea
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• v.8 no.2
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• pp.91-107
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• 1995

충남 예산-공주-청양지역의 대흥, 평안, 신양(청당)광산에서 산출되는 녹니석에 관하여 화학적 및 성인적 연구를 하였다. 이들 광상은 초염기성암기원의 사문암이 열수변질작용을 받아 생성되었다. 활석 광석의 주 구성 광물은 활석, 녹니석, 금운모, 각섬석류, 사문석, 탄산염광물 등이고 이밖에 감람석, 휘석류, 크롬철석, 스멕타이트, 녹니석/스멕타이트의 혼합층상광물들과 같은 팽윤성 광물들이 소량 산출된다. 이 중 감람석과 크롬철석은 광상의 초염기성암 기원을 지시하는 중요한 광물이다.녹니석은 활석 광석의 불순 광물 중 가장 많은 양을 차지하는 광물이다. 이들 녹니석은 성인적으로 활석과 밀접하게 연관된 녹니석과 그렇지 않은 녹니석의 두 가지 뚜렷한 타입으로 나뉘어지며 이들은 화학적으로 명확한 차이를 보인다. 전자의 녹니석은 Mg/(Mg+Fe)비가 높으며 매우 일정한 범위의 Mg/(Mg+Fe)qkl (0.784∼0.951/산소수 14 기준)를 보여주고, 높은 8면체 치환양 (0.892 (-0.200∼0.692)/산소수 14, 이상적인 클리노클로어/차모사이트 성분 기준)과 넓은 범위의 Al 함량 변화 (2.975 (1.085∼3.160)/산소수 14 기준), 높은 Cr, Ni 함량을 갖는다. 이들은 매우 제한되고 높은 Mg/(Mg+Fe)비를 갖는 환경에서 생성되었으며 따라서,활석과 밀접하게 연관된 녹니석은 생성시, 주변암에 둘러싸여 있는, 초염기성암 기원의 사문암에 의해 주로영향을 받았다. 후자의 녹니석은 전자의 녹니석에 비하여 Fe 함량이 더 놓으며 광범한 범위의 Mg/(Mg+Fe)비 (0.378∼0.852/산소수 14 기준)를 보여주고, 더 적은 범위의 8면체 치환양 (0.560 (-0.035∼0.525)/산소수 14, 이상적인 클리오클로어/차모사이트 성분 기준)과, 전반적으로는 더 높은 값을 가지면서 더 좁은 범위의 Al 함량 변화 (1.491 (1.468∼2.959)/산소수 14 기준)를 보여주며, 낮은 Cr, Ni 함량을 갖는다. 이들은 낮은 Mg/(Mg+Fe)비를 갖고 전자에 비해 Al이 풍부한 환경에서 생성되었으며, 따라서 활석과 연관되지 않은 녹니석은 생성시 광체와 인접한 화강아질 편마암에 의해 주로영향을 받았을 것으로 생각된다. 녹니석의 이러한 2가지 화학조성상의 경향은 녹니석과 공존하는 운모류나 각섬석류들의 화학분석결과와도 잘 일치한다. 이러한 결과는 이 지역의 활석 광상이 초염기성암 기원의 사문암이 열수변질작용을 받아 생성되었음을 명확하게 지시하며, 따라서 활석 광석내에 존재하는 녹니석은 활석의 근원 광물로서 녹니석편암 및 녹니석 편마암 매의 녹니석이 활석화되고 남은 잔존광물이 아니라, 주변암에 의해 성분상의 영향을 받은 열수와 사문암과의 변질교대작용에 의한 활석화과정 중에 주로 생성된 것으로 추정된다. 이러한 결과는 연구지역의 활석광상이 초염기성암의 사문암화 작용과 활석화 작용의 두 가지 변질작용에 의해 형성되어졌음을 알려준다.

• Journal of the Mineralogical Society of Korea
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• v.29 no.4
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• pp.229-238
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• 2016

This study evaluated potential application of illite, which is produced at Yeongdong area in Korea, to remove radiocesium released to environmental system through severe nuclear accidents. The Yeongdong illite was formed by metamorphose of micaceous schist in hydrothermal condition, and composed of quartz, illite, and albite. Sorption distribution coefficient ($K_d$) of cesium by the Yeongdong illite was higher than the $K_d$ values for other clay minerals. It may be affected by preferential adsorption of cesium to Frayed Edge Sites (FES) on illite. Nonlinear isotherm models were suitable to describe the sorption processes for the Yeongdong illite. Its max. single layer capacity was $250,000{\mu}g\;kg^{-1}$ for cesium. Therefore, the Yeongdong illite could be an efficient and economic sorbent to prevent dispersion of radiocesium, and apply for remediation.

• Economic and Environmental Geology
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• v.32 no.2
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• pp.129-139
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• 1999

Hydrothermal gold deposits of the Trabong district in Vietnam occur as single-stage quartz $\pm$ calcite veins (0.3-1.2 m thick) which fill fault fractures in graphite-bearing gneiss and schist of the Chulai Complex and Kham Duc Formation of the Proterozoic age. Ore grades are 1.3 to 92.4 g/ton Au. Ore mineralogy is very simple, consisting mainly of pyrite with minor amounts of base-metal sulfides and electrum. Gold grains occur in two assemblages as follows: (1) early, Fe-rich (7.2-10.4 mole % FeS) sphalerite + electrum (50.4-64.3 atom % Au) assemblage occurring as inclusions in pyrite; (2) late, Fe-poor «4.7 mole % FeS) sphalerite + galena + electrum (47.6-81.7 atom % Au) assemblage occurring along fractures of pyrites. Based on fluid inclusion data and thermochemical considerations of ore mineral assemblages, ore minerals were formed at high temperatures (about $230^{\circ}C$ to $420^{\circ}C$) from $H_{2}O-CO_{2}(-CH_{4})$-NaCI fluids with the sulfur fugacity of about $10^{-6}$ to $10^{-10}$ atm. Fluid inclusion data also indicate that ore mineralization occurred mainly as a result of fluid unmixing accompanying $CO_2$ effervescence. Calculated oxygen and measured hydrogen isotope compositions of mineralizing waters (${\delta}^{18}O_{V-SMOW}$ values = 5.3 to 8.6$\textperthousand$, ${\delta}D_{V-SMOW}$ values = - 60 to - 52$\textperthousand$), along with the sulfur isotope compositions of vein sulfides (${\delta}^{34}S_{CDR}$ values = - 1.2 to 2.8$\textperthousand$) and carbon isotope compositions of inclusion $CO_2$ (${\delta}^{13}C_{PDB}$ values = - 4.7 to - 2.0$\textperthousand$) indicate that the high temperature (mesohypothermal) gold mineralization formed from a magmatic fluid.

• Economic and Environmental Geology
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• v.31 no.5
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• pp.389-398
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• 1998

The Au-Ag deposit of the Oknam mine occurs as gold-silver-bearing rhodochrosite veins in biotite schist and phyllite of the Precambriam Yulri Group. Five stages of ore deposition are recognized, each showing a definite mineral assemblage. General mineral parageneses in veins (stage III) associated with gold and silver vary inwardly from the vein margin: arsenopyrite + pyrite $\Rightarrow$ sphalerite+chalcopyrite+galena+gold $\Rightarrow$ ga1ena+Ag-bearing minerals. Fluid inclusion data indicate that temperature and salinity of ore fluids overally decreased with time: $345^{\circ}{\sim}240^{\circ}C$ and 3.4~7.8 wt. % NaCl equiv during stage I (quartz vein mineralization), $313^{\circ}{\sim}207^{\circ}C$ and 2.3~8.7 wt.% NaCl equiv during manganese-bearing carbonate stages (II and III), and $328^{\circ}{\sim}213^{\circ}C$ and 3.6-5.4 wt.% NaCl equiv during stage IV (quartz vein mineralization). The ore fluids probably evolved through repeated pulses of boiling and later mixing with cooler and more dilute meteoric waters. Fluid inclusion data and geologic arguments indicate that pressures during the mineralization were in the range of 90 to 340 bars. Gold occurs as silver-rich electrums (21 to 29 atom. % Au) and was deposited at temperatures between $300^{\circ}$ and $240^{\circ}C$. Thermochemical calculations suggest that gold was deposited as a combined result of increase in pH and decreases in temperature, $fs_2$ and $fo_2$.

• Economic and Environmental Geology
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• v.46 no.2
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• pp.141-151
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• 2013

This study examines the mineralogy of sepiolites occurred within the carbonaceous rocks of Songak schist and Pyeongtaek migmatitic gneiss of Precambrian Seosan group, in the western part of Chungnam. Host rocks of the sepiolite were dolomitic rocks and have experienced hydrothermal alteration and metamorphism. Mesozoic granite is assumed as a main source of hydrothermal alteration for the dolomitic rocks. Some of the tremolite asbestos coexist with the sepiolites. Representative sepiolite and tremolite samples were collected from the layers cracks or fractures of the dolomitic rocks and/or examined with microscope with microscope, XRD, SEM and TEM. Sepiolites are mainly recognized along the cracks assumed as pathways of hydrothermal solution. Tremolites are mainly found at layers or cracks of the dolomitic rocks and occur as asbestos as well as non-asbestos forms. It was confirmed that some of the tremolite asbestos were coexisted with the sepiolites. Overall results suggest that the occurrences of sepiolites within the dolomitic rocks mainly result in the hydrothermal alteration and the fluid from the acidic rocks, possibly granites. It also suggests that coexisting tremolite asbestos were formed by similar geological environment.

• The Journal of Engineering Geology
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• v.4 no.2
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• pp.153-168
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• 1994

The status of groundwater development in Chungnam was studied with geological characteristics according to the measured data of Korean Rural Development Corporation. The data of 212 survey wells were used for the relation between catchment area and water discharge, and the data of 344 development wells for the relationships between well depth and discharge, between casing depth and discharge, between rock type and discharge, and the relation with lineaments density. The relationship between the catchment area and discharge does not show any special trend, and it is understood that groundwater of hard rock mass is not so much influenced by the surface catchment area. The relationship between well depth and discharge shows two different trends; discharge increasing with depth for alluvial groundwater, but no certain trend between depth and discharge for groundwater of hard rock zone. Discharge increases linearly with the casing depth, and it is reliable because the casing was installed in the weathered zone against well destruction. Generally the rock type does not show any difference of discharge, but the crystalline rocks such as granite and gneiss yield a little more discharge than the more porous rocks such as sedimentary rock or schist. It suggests that the effect of fracture zone is a major governing factor. In Hongsong and Puyo, there are similar in rock type and casing depth, but the big difference in average discharge. The big discharge of Hongsong is concordant with the higher intersection density and longer length of lineament in Hongsong than those of Puyo. Therefore the groundwater development strategy should be focused on the micro topography analysis and geophysical survey for the understanding of the fracture zone rather than catchment area or rock type.